I want to shoot my frankenjeep, running cold

[Pelican]

The stock 2.5 radiator is so different from the 4.0 POS that I can't conceive that anyone would go to the trouble to convert to one.

I guess I wasn't clear In my post #21, but I did "solve" the problem of over-cooling by swapping in the electric fan. I just didn't solve it by modifying or finding alternative stock components.

I guess it goes without saying that the 2.5 will overheat without a fan, you just want to be able to turn the fan on only when needed. I installed an indicator light in the dash so that I could tell when the fan was running. Also a switch to override the control unit in case it should be needed. All of this was relatively very easy with the space available in the 2.5 engine compartment.

I don't know if this is the best way to solve the problem but it worked for me.

 

[WarGin]

Are you sure you have the right radiator in this..? Is there a different / smaller radiator that you are supposed to have?
Still... it's hard not to keep looking at the thermostat. I mean, it's only job is to keep the engine up to temperature... and nothing else does that job, that I can think of.

Hell if I know. Jeep seemed to be smoking something when they made my car.
It's definitely not a 4.0 radiator, it's too square for that. And it's 13psi whereas 4.0 is 16 I believe. Other then that your guess as to wether or not it's the original radiator is as good as mine. For all I know it's a waggy radiator.

At the very least I made the engine bay quite a bit larger looking.

 

[techno1154]

Are you sure you have the right radiator in this..? Is there a different / smaller radiator that you are supposed to have?
Still... it's hard not to keep looking at the thermostat. I mean, it's only job is to keep the engine up to temperature... and nothing else does that job, that I can think of.

The size of the radiator should/do not matter with regards to the engine getting hot. Cooling a hot engine is a different animal all together.

The thermostat is not staying open, in fact it rarely opens at all.
I tested it 50 times, hot water (200) to cold water (room temp, probs 60)
And it opened, then closed, every single time. I actually bought 2, tested both, and took the one that opened/closed faster and installed it. It's not the thermostat.

I can only assume you run a 4.0, and not a carb'd 2.5 that puts out 120hp at best.
I think I just have too much cooling ability for the heat that my engine creates.
it too the better part of thirty (30!) minutes of idling in a heated shop before the thermostat even opened.

Yes, my XJ have a 4.0L and dual electric fans that keep the 4.0 cool in the South Florida summer stop and go traffic. I do keep an eye on the gage not for over cooling but over heating.

If the thermostat work the way it is supposed to work then I am out of suggestions. Keep working at it. I am sure that someone on here will be able to help you. It is just a matter of when they come forward.

If all else fails, try the card board in front of the radiator trick. I do that on my 1993 Toyota pickup that I DD here in Jacksonville FL. That should give you some temporary reprieve.

 

[Warlock1]

Well, there's you problem, you're missing your front exhaust manifold bolt.:gee:

 

[WarGin]

Well, there's you problem, you're missing your front exhaust manifold bolt.:gee:

It's not missing, it just decided to stay in there, and hide. :anon:
I need to replace my entire exhaust system regardless haha.
In other news I gained a few hp for sure by getting rid of that fan.
Runs so much smoother and shifts smoother.

 

[Warlock1]

Here's something that I think will help your overcooling problem.

http://go.jeep-xj.info/HowtoRadiatorRestrictor.htm

 

[8Mud]

Just for the heck of it, when the thermostat is open, squeeze the top radiator hose. When my radiator was clogged (internally) and the thermostat was open, the top hose would actually swell a little an would get hard as a rock. Typically the top hose is fairy soft, even at operating temperature and the system is fully pressurized.

Your top hose looks like a stiffer design than most, the swelling and being able to squeeze it may not work out for you.

On the 4.0 models (and most any other motor) the heater hose is also a thermostat bypass. What it does is let some of the coolant bleed around the thermostat so the thermostat is more responsive to engine temp changes. It is possible to have some fairly cold coolant pile up at thermostat when this bypass flow is restricted and it heats very slowly from the rear. You usually get some really wild temperature swings when this happens. Kind of long pulses (minutes long, sometimes 15 minute long pulses) of heated and then cold coolant flowing through the engine. This doesn't sound like your issue, but I'm out of ideas and thinking you may have some sort of one off situation and a number of issues have come together and the results are what you are experiencing.

On a hunch, put some tape on the jaws of a pair of vise lock pliers and *partially* constrict the heater hose flow and see what happens. If your top radiator hose starts to swell, it may be a tip off the radiator is partially clogged.

I once pulled a heaping handful of casting sand out of my radiator. And on a hunch, beat on the side of the block with a BFH and flushed two more handfull out of there. It was a six year old motor and not new. Point being, when the solution isn't obvious, start thinking about the really odd stuff.

As a side note, I've seen guys use the universal gasket that came with their thermostat and block off the heater hose outlet. I've seen guys use way to much RTV on the thermostat housing and the excess piled up around the thermostat jamming the valve.

I worked in an auto hobby shop (evenings) for a decade and saw all sorts of crazy stuff. If there was any way to screw it up, somebody is going to eventually do it.

 

[WarGin]

Just for the heck of it, when the thermostat is open, squeeze the top radiator hose. When my radiator was clogged (internally) and the thermostat was open, the top hose would actually swell a little an would get hard as a rock. Typically the top hose is fairy soft, even at operating temperature and the system is fully pressurized.

Your top hose looks like a stiffer design than most, the swelling and being able to squeeze it may not work out for you.

On the 4.0 models (and most any other motor) the heater hose is also a thermostat bypass. What it does is let some of the coolant bleed around the thermostat so the thermostat is more responsive to engine temp changes. It is possible to have some fairly cold coolant pile up at thermostat when this bypass flow is restricted and it heats very slowly from the rear. You usually get some really wild temperature swings when this happens. Kind of long pulses (minutes long, sometimes 15 minute long pulses) of heated and then cold coolant flowing through the engine. This doesn't sound like your issue, but I'm out of ideas and thinking you may have some sort of one off situation and a number of issues have come together and the results are what you are experiencing.

On a hunch, put some tape on the jaws of a pair of vise lock pliers and *partially* constrict the heater hose flow and see what happens. If your top radiator hose starts to swell, it may be a tip off the radiator is partially clogged.

I once pulled a heaping handful of casting sand out of my radiator. And on a hunch, beat on the side of the block with a BFH and flushed two more handfull out of there. It was a six year old motor and not new. Point being, when the solution isn't obvious, start thinking about the really odd stuff.

As a side note, I've seen guys use the universal gasket that came with their thermostat and block off the heater hose outlet. I've seen guys use way to much RTV on the thermostat housing and the excess piled up around the thermostat jamming the valve.

I worked in an auto hobby shop (evenings) for a decade and saw all sorts of crazy stuff. If there was any way to screw it up, somebody is going to eventually do it.

The upper radiator hose looks stiff because it is lined with a wire coil to keep it from collapsing i guess. I only put it in because I got really, really frustrated with the guy behind the desk at the autoparts store, he tried selling me what he said was the oem radiator hose (also 60 bucks), but was 3x longer then it needed to be and was shaped all weird. I needed 1.5" to 1.25" ,so i just got 1.5 and ran it. that was "all they had" apparently. My original hose pretty much disintegrated in the parking lot so i didnt really have a choice haha

The thermostat is free to open, theres no RTV only the gasket that came with the housing, and the thermostat bypass (which goes to the heater core as well on the 2.5) is also clear.
i guess the only difference between our systems is that i have hoses going into and out of my intake manifold to heat the fuel/air mix in between the tstat and my heater core.

When this whole escapade started the coolant was muddy, but we flushed everything, including the block, till it came out clean. It has remained green thus far, although it has been added/taken away alot.

As of right now im running from 130 while driving to 170 at a red light, 190 if theres a line.

And I will look into that restrictor for sure, thanks Warlock1.

Well, I have heat now, so I guess that problem is solved.
Thanks everyone for your help.

 

[Warlock1]

Sure, no problem.

This might be a dumb question, but, is there anyway that the thermostat could be in backwards? I know most times it will not fit if put in the wrong direction, but, maybe? Might be worth a try. It almost looks like there might be enough room.

 

[Digger87xj]

a t-stat installed backwards would cause overheat. The bulb of the t-stat should be inside the engine. I don't think it will fit the other way.

your temp gauge install looks a little dubious.. it will read cold.

Forget the drilling a hole in the t-stat.. it is not needed, obviously.

 

[WarGin]

a t-stat installed backwards would cause overheat. The bulb of the t-stat should be inside the engine. I don't think it will fit the other way.

your temp gauge install looks a little dubious.. it will read cold.

Forget the drilling a hole in the t-stat.. it is not needed, obviously.

I thought the temp guage would read cold too, till I tried it. It was 10 seconds behind the reading on the IR gun.